there are couple different options for bridging..
you can run the 1-alpha solo until you are ready to add the epiV, and run both together for a week before running epiV solo
you can run the 1-alpha, bridge into 550xd as you mention, then finish with epiV, using all of these products individually/consecutively
you can run the 1-alpha until you are ready to add the 550, combine the two for a week (as i mention up top)..go into 550 solo, until you are ready to add epiV, then combine these two for a week before going epiV solo
lots of choices, depending on how extensive you wish to get
as for running PCT Black during cycle - you can do that if you wish, but this wouldn't be necessary, unless you experience symptoms of heightened estrogen..otherwise, i would actually save PCT Black for pct (you can begin running in final week of epiV if you wish, in the same fashion i have described bridges above..this would be to get a head-start on pct
you can also add your DAA in the same fashion, as you would PCT Black above (then continue running DAA for couple weeks after completion of pct)